Disclosed herein are processes for treating high-P fluids involving (1) providing a high-P containing stream; (2) chemically treating the high-P stream such that a majority of dissolved P in the stream is transformed into a solid form via sorption of P onto particles placed or precipitated within the stream; and (3) removing the solid form containing P from the chemically treated fine solids stream, such that > about 90% of the total P is removed from the high-P fluid. Also disclosed are systems for treating a high-P stream, the systems involving (1) a chemical treatment station operable to chemically treat and transform equal to or greater than about 90% of dissolved P in a high-P stream into a solid form; and (2) a liquid-solid separator station operable to remove the solid form containing P from the chemically treated high-P stream.
Managing manure phosphorus (P) has become a priority concern of livestock operations, in part due to nutrient management implications with land application of manure. Concentrated livestock production occurs in many regions of the country and is associated with regional and farm-scale accumulations of P due to the nature of feed nutrients and metabolism by the animal, with manure P typically containing more than two-thirds of consumed feed P (Hristov, A. N., et al., J. Dairy Sci., 89: 3702-3712 (2006)). These accumulations have, over time, created a legacy of P sources that can enrich runoff water and contribute to downstream eutrophication, the most pervasive water quality problem in the US, which accounts for about 66% of the impaired conditions of US rivers (Carpenter, S., et al., Ecol. Appl., 8: 559-568 (1998)). Compounding the legacy effect of regional and farm P accumulations is the imperfect ratio of N and P in most livestock manures when used as a fertilizer source. Elevated concentrations of P in manure relative to N results in excess application of P to agricultural soils when manures are applied to meet crop N demand (Sharpley, A. N., et al., J. Env. Qual., 23: 437-451 (1994)). Few options are available to efficiently move manure P from areas of surfeit to areas of deficit and few options exist to adjust manure nutrient ratios to better fit crop demand (Sharpley et al. 1994; Kleinman, P., et al., J. Soil and Water Conserv., 67: 54A-61A (2012)).
A variety of approaches have been proposed to treat animal manures to reduce their potential for adverse environmental impact. Most successful has been the use of aluminum (Al), iron (Fe) and calcium (Ca) salts as manure amendments to reduce the solubility of P, thereby decreasing the potential of manure to enrich dissolved P in runoff water (Moore, P. A., Jr., and D. M. Miller, J. Env. Qual., 23: 325-330 (1994); Smith, D. R., et al., J. Env. Qual., 33: 1048-1054 (2004); Irshad, M., et al., Can. J. of Soil Sci., 92: 893-900 (2012)). Indeed, the application of alum (Al2(SO4)3) to poultry litter has also been shown to improve the conservation of NH4—N in manure due to the weak acidic properties of alum (Moore, P. A., Jr., et al., J. Env. Qual., 29: 37-49 (2000)). However, amending manures to reduce manure P solubility does not change the N:P ratio in manures and does not address the accumulation of P on farms. To achieve that objective, removal of P is necessary while conserving sufficient N to create an N:P ratio more favorable to crop production.
We have developed systems and processes for economically treating animal manure and other by-products that can be applied to land to reduce their phosphorus content. In addition, the systems can be compact and mobile.